JPS603513A - Position and speed detecting device of moving body - Google Patents

Abstract

PURPOSE:To obtain a device which is resistant to an electromagnetic noise and is capable of detecting a position and a speed by scarcely causing detection errors, by laying an optical fiber along a track part, applying a magnetic field to light in the optical fiber from a magnet of a moving body, rotating a plane of polarization of light, and detecting and counting it. CONSTITUTION:An optical fiber 6 is constituted of a vertical part 6a and a parallel part 6b in the running direction of a car body 5. A light emitting device 7 using a laser light source is provided on one end of the optical fiber 6, and a photodetecting device 8 is provided through a polarizer 6c on the other end of the optical fiber 6. In this state, coherent light 9 polarized in a prescribed direction is transmitted in the optical fiber 6. Whenever an electromagnet 10 passes through the vertical part in the running direction of the car body of the optical fiber 6, a magnetic field of the direction parallel to said part is applied to the vertical part 6a of the optical fiber 6. As a result, whenever the car body 5 passes through the vertical part 6a, the light 9 in the optical fiber 6a generates what is called ''Faraday polarization'' by the magnetic field from the electromagnet 10, and the plane of polarization of the light 9 is rotated by a prescribed angle.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a device for detecting the position and speed of a moving body moving along a rail or track section laid on the ground.

[Prior art and its problems]

BACKGROUND ART Conventionally, for example, an inductive radio system has been employed to detect the position and speed of a linear motor car, as shown in FIG.

In Fig. 1, reference numeral 1 denotes a guide wire formed in two strips by reciprocating between the starting end and the terminal end of the track along a track laid on the ground. It is connected to a receiving circuit 2 installed at the starting end of the section. The guide wires 1 are twisted at a constant pitch, and twisted intersections 3 are provided at constant distances along the track.

Reference numeral 4 denotes a traveling antenna mounted on the vehicle body 5 of the linear motor car, and the traveling antenna 4 moves along the guide line 1 in the left-right direction in FIG. 1 together with the vehicle body 5.

Each time the traveling antenna 4 passes by the twisted intersection 3, it detects a decrease in the reception level or a phase change, and
The number of twisted intersections 3 that the vehicle body 5 has passed is counted. The position of the vehicle body 5 is determined by multiplying the counted value by the distance between the intersections 3, and the traveling speed is determined by the counted value per unit time.

However, since the above-described guided radio system utilizes the induced electromagnetic field generated around the guided wire 1, the transmission characteristics change due to the magnetic material or metal piece present near the guided wire 1. Furthermore, if the feeder wire or current collector wire is located near the guide wire 1, it is likely to receive electromagnetic induction from them. In particular, linear motor cars are equipped with current collection lines, linear motors, levitation/guidance electromagnets, etc., and the inductive radio system is extremely susceptible to the effects of electromagnetic induction from these.

Therefore, conventional position and speed detection devices using guided radio methods are susceptible to noise and have many detection errors, making them particularly unsuitable for linear motor cars and having the disadvantage that they can only be installed in areas with low noise. There is.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks of conventional position and speed detection devices, and to provide a position and speed detection device that is resistant to electromagnetic noise and has little detection error.

[Key points of the invention]

In the present invention, an optical fiber formed into a certain wave shape is laid in the moving direction of the moving object, and one end of the optical fiber is provided with a light projecting means, and the other end is provided with a light detecting means for receiving light passing through the optical fiber. On the other hand, the movable body is provided with magnetic field generating means for applying a magnetic field in a fixed direction to the optical fiber. and,
Each time the magnetic field traverses a particular portion of the corrugated optical fiber as the moving object moves, the magnetic field causes polarization in the optical fiber. Therefore, the optical detection means produces a change in output every time the magnetic field crosses the optical fiber, and the position or speed of the moving body can be detected from the number of changes in the output.

[Embodiments of the invention]

In FIG. 2, reference numeral 6 denotes a rectangular wave-shaped optical fiber provided along the track of the linear motor car. Ru.

The distance between each vertical portion 6a of the optical fiber 6 is equal. A light emitting device 7 using a laser light source is provided at one end of the optical fiber 6, and a light receiving device 8 is provided at the other end of the optical fiber 61 via a polarizer 6C. Then, coherent light 9 polarized in a certain direction is transmitted through the optical fiber 6.

10 is a car body 5 so as to sandwich the optical fiber 6 on the track section.
A set of electromagnets attached to the bottom of the
The coil is connected to a DC power supply device 11 mounted on the vehicle body 5. Then, the electromagnets 10 of the negative set run in the left-right direction in FIG. 2 together with the vehicle body 5 while holding the optical fiber 6 between them.

In addition, a magnetic field as shown by the dashed line in FIG. Each time it passes through the section 6a, the vertical section 6a of the optical fiber 6 has a
Apply a magnetic field in a direction parallel to that.

As a result, each time the vehicle body 5 passes through the ice coating portion 6a, the light 9 in the optical fiber 6a produces so-called Faraday polarization due to the magnetic field from the electromagnet 10, and the polarization plane of the light 9 rotates by a predetermined angle. On the other hand, each parallel portion 6 of the optical fiber 6
In b, the direction of the magnetic field from the electromagnet 10 is perpendicular to the traveling direction of the light 9, so the plane of polarization of the light 9 does not rotate.

Due to the Faraday polarization of the light 9, the amount of light received by the light receiving device 8 changes, so the output of the light receiving device 8 changes every time the electromagnet 10 passes through the vertical portion 6a. Then, the number of changes described above is counted by a counting device 12 connected to the light receiving device 8.

By multiplying this count by the distance between the vertical portions 6a of the optical fibers 6, the distance of the vehicle body 5 from, for example, the light emitting device 7 is detected, and the position of the vehicle body 5 is detected. Furthermore, the speed of the vehicle body 5 is detected by counting the number of times the light 9 is modulated per unit time.

3 and 4, as the electromagnet 10 of the above-described embodiment, an on-vehicle electromagnet 13 for a near motor is attached to the vehicle body 5.
Another example using .

As shown in FIG. 4, the on-board electromagnet 13 for the linear motor is connected to track sections 14 laid on the ground on both sides of the lower part of the vehicle body 5.
It is attached so as to sandwich it. On the other hand, on both sides of the track section 14, a ground coil 15 is installed on the on-board electromagnet 13 for the linear motor.
It is formed continuously so as to face the Then, a propulsive force acts between the on-board electromagnet 13 for the linear motor and the ground coil 15, and the vehicle body 5 travels floating by floating equipment (not shown) without contacting the track section 14.

In order to use the on-board electromagnets 13 for linear motors together for position and speed detection, the polarities of the on-board electromagnets 13 for linear motors should be opposite to each other, and the vertical portion 6a of the optical fiber 6 should be aligned with the linear motor. The optical fiber 6 may be laid in the center of the track section 14 so that an axial magnetic field is applied from the on-board electromagnet 13 for the motor.

Since the on-board electromagnet 13 for linear motor is long in the running direction,
As shown in FIG.
There is a possibility that a magnetic field is simultaneously applied to the on-board electromagnet 13 for the linear motor.

In this case, the light 9 may be modulated at multiple locations at the same time, leading to inaccurate detection of the position and speed of the vehicle body 5.

In order to prevent this, each vertical portion 6a of the optical fiber 6 must be
, with an iron magnetic shield 14 that blocks the magnetic field,
Just cover every other one. Then, the effective spacing between the optical fiber vertical portions 6a is doubled, and the linear motor on-board electromagnet 13 modulates the light 9 only in one optical fiber vertical portion 6a where the magnetic shield 14 is not provided at a time.

If the linear motor on-board electromagnet 13 is longer in the running direction than shown in FIG. 3, only every second or third optical fiber vertical portion 6a is exposed and other optical fiber vertical portions are exposed. 6a may be provided with a magnetic shield 14 to double or triple the effective spacing.

In the embodiment described above, the optical fiber 6 is not affected by electromagnetic induction from nearby linear motors, levitation electromagnet current collection lines, etc., and position and speed can be detected accurately and noise is eliminated. The above-described embodiments can be used even in areas with high standards. 1. The present invention is particularly effective for linear motor cars, but can also be applied to detecting the position and speed of other moving bodies such as cranes and transport vehicles.

〔Effect of the invention〕

As detailed above, according to the present invention, an optical fiber is laid along a track section, a magnet is mounted on a moving body, and a magnetic field is applied to light in the optical fiber from the magnet of the moving body. By rotating the plane of polarization of light and detecting and counting it, the position and speed of a moving object can be detected, making it resistant to electromagnetic noise and can be used even in areas with high noise levels. , it is possible to provide a position and velocity detection device with little detection error.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a position/velocity detecting device using a conventional guided radio method, FIG. 2 is a block diagram showing one embodiment of the present invention, FIG. 3 is a block diagram showing another embodiment, and FIG. The figure is a sectional view of the linear motor car showing the embodiment of FIG. 3. 6... Optical fiber, 5a... Vertical portion of optical fiber, 10... Electromagnet, 13... On-board electromagnet for linear motor, 5... Vehicle body, 14... Track portion, 7... - Light emitting device, 8... Light receiving device. Patent applicant: Sumitomo Electric Industries, Ltd. Patent attorney Aoyama Hogai (1 person). No. 16 1N Kaisho GO-3513 (4) Fig. 4 51)

Claims (1)

[Claims] (1) An optical fiber formed into a certain wave shape is laid in the moving direction of the moving object, and one end of the optical fiber is provided with a light projecting means,
The position and speed of a moving object, characterized in that the other end is provided with a light detection means for receiving the light passing through the optical fiber, and the moving object is provided with a magnetic field generating means that applies a magnetic field in a fixed direction to the optical fiber. Detection device.